Remove react-native-exit-app from nightly testing (facebook#51230)

Summary:
Pull Request resolved: facebook#51230

react-native-exit-app last commit is from 2 years ago.
Removing it as it is broken with our nightly integration

## Changelog:
[Internal] - Remove react-native-exit-app from nightly testing

Reviewed By: cortinico

Differential Revision: D74527792

fbshipit-source-id: 0974b2d857aa6f76c59b0411204798a5fe48cffe

Author: cipolleschi

.github/workflows/test-libraries-on-nightlies.yml

@@ -48,7 +48,6 @@ jobs:
           "react-native-contacts",
           "react-native-device-info",
           "react-native-email-link",
-          "react-native-exit-app",
           "@dr.pogodin/react-native-fs",
           "react-native-permissions",
           "react-native-vector-icons",